Latch



May 20, 1941. K. BEYRODT 2,242,385

LATCH Filed Jan; 28, 1939 Z SheetS-Sheet 2 fig. 1]

. mfg w KURT 5524200? Patented May 2c, 1941 4 Claims.

The present invention relates to latches and more particularly to alatch for doors or other type closures.

An aim of the present invention is the provision of a latch which isparticularly suitable for use on the closures of devices wherein a fluidor gas seal must be maintained or is highly desirable, such as inrefrigerators Or as in the toilet seat sterilizer disclosed in PatentNo. 1,877,689 to R. E. Peterson, and also on devices wherein there is atendency of the closure to rattle or unlatch due to vibration, as, forexample, in automobile doors.

An object of the invention is the provision of a latch for such use,which latch, upon being released, is self-closing and maintains aconstant tension, tending to urge the closure to closed position.

A still further object is a latch having a bolt which is normally urgedto closed position and wherein means are provided, upon the bolt beingretracted, to automatically hold it in retracted position, and thus noparts project beyond the edge of the closure.

A still further object is a latch having switch means associatedtherewith, which means are operable upon movement of the bolt towardsopen and closed. position.

A still further object is a latch of this type having a minimum numberof parts, which latch may be readily manufactured and is adapted to awide variety of uses.

Other objects will be in part obvious and in part pointed out more indetail hereinafter.

The invention accordingly consists in the features of construction,combination of elements, and arrangement of parts which will beexemplified in the construction hereafter set forth and the scope of theapplication of which will be indicated in the appended claims.

In the accompanying drawings:

. Figure 1 is a front View of the latch as seen when mounted on aclosure;

Fig. 2 is a side view partly in section showing the latch in latchingposition and. wherein a cam follower is associated with the boltdrawback;

Fig. 3 is a side sectional View showing the latch in retracted positionand moving towards closed position;

Fig. 4 is an end view of retracted position;

Fig. 5 is a perspective fragmentary view showing the details of thebolt;

Fig. 6 is a front view of the cooperating latch the latch as seen instriker plate;

Fig. 7 is a perspective view of the plate shown in Fig. 6;

Fig. 8 is a rear view of the latch showing the cooperating switch means;v

Fig. 9 is a side view partly in section of another modification of thelatch shown in its latching position;

Fig. l0 is a sectional view of the latch shown in Fig. 9 with the boltin retracted position;

Fig. 11 is a front view of the latch shown in Figs. 9 and 10 with partof the casing removed;

Fig. 12 is an end view of the latch shown in Fig. 11;

Fig. 13 is a perspective ,view showing the details of the bolt andcooperating holding means therefor; and

Fig. 14 is a perspective view of a modified form of striker.

Referring to the drawings, and more particularly to Figs. 1 .to 8, thelatch A is shown mounted on a surface B which may be a door hinged toswing into and out of engagement with adoor jamb C carrying acooperating striker plate D; the latch and striker being equallyefficient and operative if mounted on the opposite members.

The latch A comprises a casing having a front wall 20, side walls 22, arear wall 24, and an end wall 26. As indicated, the rear, side, and

end walls may be stamped from a single piece of metal, and the sidewalls may be provided with outwardly projecting flanges 25 adapted to bespot welded to the front wall 20 to provide a substantially rectangularbolt casing adapted to be securedto a door or the like by suitablescrews 32 extending through aligned openings in the front wall 20 andside flanges 25. The front wall 20 may also be provided with inwardlyextending lugs 33 adapted to extend behind the end wall 26 to positionand reinforce same.

The bolt housing or casing has positioned therein a latching bolt 34comprising a rectangular body portion 35 and a latching pawl 3'! havingone end pivotally connected to the body portion and its other end freeto swing in the arc of a circle. The bolt body portion 35 comprises aone-piece rectangular member having a longitudinally extending bore 36open at its inner end thereof and in which there is positioned a spring38 which, bearing against the forward wall 35 of the bore and againstthe end wall 26 of the casing, normally urges the bolt outwardly tolatching position. In order to withdraw the bolt, there may be providedan operating member 40 secured in the bolt and projecting from thecasing through an elongated slot 42 in the front plate 20, as shown inFigs. 1, 3, and 4, or as shown in Fig. 2, a cam follower 44 may beutilized if the latch is to be mechanically operated.

The outer end of the body portion 34 carries two forwardly extending armor wing members 46 having substantially the shape of a right angletriangle, with the smaller leg thereof adjacent the front wall 20 of thelatch casing. The wing members 45 are provided at the apex with alignedapertures 48 adapted to receive a transverse pin 50 to provide a supportfor the latching or bolt pawl 31.

The pawl 31 comprises a substantially U- shaped member having a base 53and two forwardly extending spaced parallel arms 54. The base 53 isprovided with a transverse bore adapted to receive the transverse pawlsupporting pin-- 50 and thus pivotally mount the pawl 31 on the end orwing member 46 of the bolt body 35. The two forwardly extending parallelarms 54 are also provided with aligned apertures Bit-arranged on thecenter line 51 of the pawl arms and adapted to receive a pin 58having-rotatably mounted thereon intermediate of the arms a latchingpawl roller 50. As best seen in Fig. 5, the ends of the pin 58 extend toeither side of the arms 54 and serve to properly position the pawl androller when the bolt has been retracted, as hereinafter described.

In the present invention, the bolt not only latches the door in closedposition, but is selfholding within its casing when in retractedposition, whereby no parts project from the edges of the closure when itis in open position. This 3 is accomplished by providing the pawl 3!with means for normally pivoting the free end thereof about the pin 50;said means comprising a spring 62 and having one end 64 abutting theforward end of the latch bolt and its other end 65 hooked over the uppersurface of one of the latch'arms 54. The spring is coiled about pin 50in a direction to normally pivot the pawl against rear wall 24 andposition it behind suitable retaining means 10 carried thereon.

In the embodiment illustrated, the retainer 10 1 comprises a cross bardefining the forward edge of a rectangular opening 58 provided in wall24 and having a width slightly greater than the width of the latchingpawl but less than that of the pawl positioning pin 58. Thus when thelatch bolt is drawn rearwardly, the spring 62 will automatically rotatethe pawl to urge the pawl roller 60 into-the opening 68 behind theretainthat the releasing plate thereof will lie parallel to the frontplate 20 of the latch casing when the closure has been moved to itsclosed position. There is mounted on the plate 14 a releasing lug 19adapted to project into plate opening 68 and abut one of the arms 54 oflatching pawl 31 and lift the free end thereof from behind retainer 70.

The amount of force necessary to release the pawl 31 from behind theretainer 10 is relatively small inasmuch as it is merely necessary toraise the pawl sufficiently to raise the forward end of a center line5'! extending through the center of pins and 58 (see Fig. 3) above theupper edge H of the retainer; it being apparent that by changing theline of centers of the two pins relative to the retainer 10 the amountof force necessary may be increased or decreased.

As the bolt is urged forwardly by the spring 38, the pawl roller willengage the centrally arranged cam seat 18 of the plate 16 and, due

tothe forward motion ofthe latching bolt, be guided thereby into theretaining seat 82 with the free end of the pawl pivoting about thepin 50as a center.' The retaining seat is so located "that when the roller 60-is seated therein, the

centerthereofwill be in a plane above the center of the pin 50;whereupon a toggle action results with both pin 50 and pin 58 acting aspivot centers. With the toggle created, the tendency of the body portionof the bolt will be .to continue to move forwardly in the direction ofthe arrow, as seen in Fig. 2, and carry the pin 50 towards verticalalignment with the pin 58. A continuous force is thus exerted .by thebolt against the striker plate seat 82; maintaining a continuousself-closing action, constantly urging the door ing cross member 10,with the pivot centerthereof beneath that of the pin 50 and the centerline through the pivots intersecting retainer 10 beneath the upper edge1 I.

The pawl roller 60 is prevented from passing completely through theopening 68 by the ex-' tending ends of positioningpin 58 which rest onthe flanges 13 which define the side edges of the opening 68, and thusthe bolt is restrained in retracted position against the normal tendencyof spring 38 to urge it to its latching position.

There is further provided a strike plate D adapted, when the latchmoves'to latching position, to cooperate therewith, whereupon the latchwill exert and maintain-a constant tension tending to move the doortowards closed position at all times after the latch has-zbeen released.To accomplish this, the strike plate D comprises a releasing plate 14and a cam carrying plate 16 arranged at right angles to-the releasingplate. i The strike plate is so-mounted towards closed position, andlikewise preventing any rattling thereof.

The construction shown in the foregoing figures' is particularlyadvantageous in structures wherein a gasor liquid-tight seal isessential. It has been found to be highly emcient and effective whenused in closing and maintaining closed the sterilizer compartment doors54 of the toilet seat sterilizer shown in the above-mentioned patent toPeterson No'.-1,87'7,689. When so used the spring member 38 is heavilyloaded and mechanically operable cam means are providedfor withdrawingthe bolt, and the latch is also so positioned that it cannot beaccidentally released. 7

When used in conjunction with said patent, it is also desirable toprovide switch means actuated by the bolt to open and. close a suitablesafety circuit. As-bes't seen in Fig. 8, the switch arms may bemountedbetween suitable insulating blocks 8| mounted-on one of the sideplates 22. The switch comprises a lower spring contact carrying arm 83having a normal tendency to spring downwardly .and'adapted to be urgedupwardly into engagement with a second contact carrying. arm 84. The arm84 likewise has a normal .tendency to move downwardly, but is maintainedin upper position by a suitable holding leaf 86. The arm 83 iscontrolledby a ball 88 positioned in an opening 92 in the sidewall ofthe casing and adapted, when the bolt is in retracted position, to dropinto a suitable conical recess 90 provided therein. As is apparent; whenthe bolt is urged forwardly the ball will roll up onto the flat sidesurface of the bolt, carrying spring action of the contact arms 83 and84. Due to the rapid action of the bolt, a fast make and break of thecontact results, making the switch particularly suitable for many uses.

There is shown in Figs. 9 to 13 an embodiment which is particularlysuitable for use such as on refrigerators or the like. As in the firstembodiment, there is provided a casing having a front plate 94, a rearplate 96,'side channel members 98, and an end wall 99. The plates may bemetal stampings or extruded shapes and, when assembled, secured as byspot welding to provide a rectangular casing for receiving the bolt I00.The bolt I may likewise be stamped and bent or cut from extruded stockto provide a rectangular open-ended body portion It provided withforwardly extending wing members I02 on which there is pivotally mounteda latching pawl I 04, as in the prior embodiment.

For retaining the spring I06 within the bolt, there is provided asuitable U-shaped member I08 positioned within the bolt with the baseI09 thereof closing the forward end of the bolt body portion NH. Thelegs of member I08 may have outwardly projecting lugs IIO positionedwithin suitable recesses I I2 in the rear side edges of the bolt bodyportion IOI to further assist in positioning same.

Inasmuch as the embodiment illustrated is intended for use such as onhousehold refrigerators, the rear plate 96 thereof has a relativelysmall opening II3 cut therein, and the forward cross bar is stampedupwardly to provide a pair of spaced apart latch retainers I I4.

With this construction, the pawl roller, when in retracted position, isheld above the plane of the rear plate and, therefore, cannot bereleased by accidentally striking it or intentionally pushing it outwith a finger. In order to release the pawl I04, the cam member II6 ofthe striker is provided with a forwardly extending portion II8 adaptedto enter between the retaining members I I4 and engage the pawl rollerjust prior to the time that the closure reaches closed position,whereupon the retainers will move away from the roll and thus releasethe bolt.

As the pawl has come in contact with the striker plate cam while therelative velocity between the pawl roller and the striker plate issmallor practically zero, the pawl roller will continue to ride along the camuntil it is positioned in the cam seat I05. Thus no contact between themetal parts is established while the relative motion between them is ofa high degree and the latch for all practical purposes is silent in itsoperation.

It will also be noted that the pawl I04 is made substantially longerthan in the prior embodiment, thus giving a greater toggle action afterthe latching pawl has become seated, permitting the use of a relativelylight spring, which is desirable when the latch is to be manuallyoperated.

There is also provided a handle member I20 mounted on the outer end of ashaft I22 suitably pivoted in the front and rear plates 9d and 96.Extending from the inner end of the shaft is rollback I24 having itsinner end positioned in a suitable slot provided therefor in the rearwall I26 of the bolt body portion IOI. As best seen in Fig. 11, theinner end of shaft I22 is provided with a pin I2I positioned within anangular slot I23 in rollback I24 to provide an angular lost motiontherebetween equal to the angular motion of the handle. Mounted on theshaft is a disturbed.

spring I25 having one end secured in the front plate 94 and the othersecured to the shaft and so coiled as to normally tend to rotate thehandle I20 in a counterclockwise position, as seen in Fig. 11. As inprevious embodiments, a suitable switch might be mounted thereon; itbeing com.- mon practice in domestic refrigerators to have a lightoperated upon the opening of the door, and the switch could readily beutilized for the control of said light.

Thus when the bolt is in retracted position, the pin IZI will bepositioned against the forward shoulder I230. of the slot I23, anduponthe release of the latch the rollback will move relative to the shaftand the handle I20 will not be In latching position, the shoulder 2312will be adjacent the pin I2I, where, upon rotation of the handle, thebolt will be retracted, and, upon releasing of the handle, the springI25 will return the handle to the normal position shown in Fig. 11.

There is shown in Fig. 14 a modified striker plate comprising a cam I28made of a. suitable resilient material bent to provide a latching seatI30 spaced downwardly from the upper rigid wall member I3I by arearwardly and upwardly extending tongue I32. The tongue I32 tenninatesin a T I34 slidably positioned in a suitable recess I36 in the rigidwall member I3. Positioned forwardly of the recess is an adjustmentscrew I38 vertically arranged in the rigid wall member I3I and adaptedto engage the tongue I32 above the latch-receiving seat I30. The screwI38 permits the seat to be adjusted in a plane perpendicular to that oftheclosure, whereby a maximum sealing tension between the closure andjamb may be obtained. Due also to the natural resiliency of the striker,the noise of closing may be greatly reduced, and likewise when thelatching pawl is positioned in the seat I30 and tends to force thetongue I32 upwardly, there is a natural tendency of the cam to actagainst the pawl, thus increasing the tension for maintaining the doorin closed position.

As many changes could be made in the above construction and manyapparently widely different embodiments of this invention could be madewithout departing from the scope thereof, it is intended that all mattercontained in the above description or shown in the accompanying drawingsshall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the language used in the followingclaims is intended to cover all of the generic and specific features ofthe invention herein described and all statements of the scope of theinvention which, as a matter of language, might be said to falltherebetween.

I claim as my invention:

1. In a latch of the character described, a casing, a bolt positioned insaid casing, a pivoted latching pawl carried by the bolt, a light springnormally urging said latching pawl in one direction, heavy spring meansnormally urging said bolt and pawl to latching position, a keeperagainst which said latching pawl is adapted to strike, said keeperincluding a cam terminating in a seat located above the pivot of saidlatching pawl, said heavy spring means for urging said bolt forwardlybeing of sufficient strength to pivotally carried by said bolt, andspring means normally urging said bolt in one direction, a keeperagainst which said pawl is adapted to strike, and second spring meansnormally urging said bolt to latching position and of such strength thatit will overcome said first spring means and causesaid latching pawl topivot on said strike into latching position.

4. In a latch of the character described, a casing, a boltslidablypositioned in said casing, spring means normally urging saidbolt to latching position, bolt retaining means within said casing, alatching pawl pivoted to said bolt, spring means normally urging saidpawl in a direction to engage behind said retainer means and maintainsaid bolt and pawl in retracted position, a keeper-against which saidpawl is adapted to strike, said keeper including a cam and a latchingseat positioned above the pivot of said latching pawl, means carried bysaid keeper for urging said pawl from behind said retaining means,whereby said bolt springmeans will urge said pawl into engagement withsaid keeper and pivot it into said seat to establish a toggle link underconstant spring pressure.

KURT BEYRODT.

